Fluid-operated control system



Feb. 1 8, 1947. I w w. SLOANE FLUID-OPERATED CONTRO L SYSTEM 3 Sheets-Sheet 1 Original Filed Aug. 28; 1942 Q5 k R Arron 615v 5 Sheets-Sheet 2 w. w. SLOANE FLUID-OPERATED CONTROL SYSTEM Original Filed Aug. 28, -1942 Feb. 18, 1947.

70R 7 have M awn Er Patented Feb. 18, 1947 UNITED STATES PATENT OFFICE 2,415,915 FLUID-(BPERATED CONTROL SYSTEM ti illiarn W. Sloane, Chicago, 111., assignor to Goodman Manufacturing Company, Chicago, 111., a corporation of Illinois 2 Claims.

This invention relates to a fluid-operated control system particularly adapted to control the electric circuits of electric motors used to propel mine locomotives, but not necessarily limited to such use.

The principal objects of the invention are to provide a novel and compact form of control system for an electrical circuit particularly adapted to control the operation of a mine locomotive in a more positive and efncient manner than formerly, which does away with all electrical connections in the operators cab, so as to increase the safety of the locomotive and save space in said cab.

A further object of my invention is to provide a new and improved controller wherein the electrical connections are at a distance from the operator, close to the devices they control, and wherein fluid pressure means located outside of the casing of the controller proper are provided to operate the electric contacts.

A more specific object of my invention is to provide a fluid-operated controller particularly adapted for starting the motor of a mine locomotive and controlling operation thereof, and in- L eluding a novel form of distributor valve for supplying fluid at pressures increasing or decreasing step by step, to successively close or open the electrical contacts controlling the electrical circuit of the locomotive, together with a. novel form of control valve for controlling operation of said distributor valve by supplying fluid under pressure thereto at pressures positively increasing step by step by predetermined values, and decreasing in the same manner.

This application is a division of application Serial No. 456,490, filed August 28, 1942, and entitled Fluid-operated control systems, now Patout No. 2,383,894, dated August 28, 1945.

Other objects and novel features of my invention will appear from time to time as the following specification proceeds and With reference to the accompanying drawings wherein:

Figure l is a diagrammatic view illustrating an electrical control circuit for two motors of an electrical device such as a locomotive, and showing the fluid circuit for controlling operation thereof;

Figure 2 is a transverse sectional view taken through a controller constructed in accordance with my invention and showing a distributor valve connected thereto, for supplying fluid under pressure thereto;

Figure 3 is a top plan view of a casing for a reverse drum, with a fluid motor for operating the reverse drum shown in horizontal section;

Figure 4 is a fragmentary view side elevation of the control casing, showing the valve for operating the reverse drum in transverse section;

Figure 5 is a view in side elevation of the con 2 trol valve, for supplying fluid to the distributor valve under different pressures, with parts of the valve shown in section;

Figure 6 is a top plan view of the valve shown in Figure 5, with certain parts of the valve shown in horizontal section;

Figure 7 is a fragmentary detail view in side elevation of the valve shown in Figure 5, with certain parts shown in section, and illustrating more clearly certain details of the interlocking connection between the valve which controls reversal of the control circuit; and

Figure 8 is an enlarged detail partial fragmentary longitudinal sectional view of the intermediate pressure control valve of the control valve illustrated in Figures 1, 5 and 6.

In Figure l of the drawings an electrical control circuit is shown which is particularly adapted to control the simultaneous operation of a plurality of motors, preferably the motors of a mine locomotive, and a hydraulic control system arranged in accordance with my invention, is shown for controlling operation of the electrical contacts of this control circuit. The motors are herein shown as being connected in parallel for simplicity, it being understood that the electrical control circuit may be so arranged as to connect them in series or in series parallel, or in any other desired manner. Said motors each consist of an armature Ill and a field H, and starting and stopping thereof is controlled by an electrical controller generally indicated by reference character l2. Said controller includes a plurality of fluid-operated contactors I, 2, 3, 4, 5, 6, T and 8, for connecting the motors in the pOWer line and for progressively cutting sections of a resistance 13 from the motor circuit.

The controller l2, as illustrated in Figure 2, includes a casing M forming an enclosure for the contactors I to 8 inclusive. Said contactors are each of the same construction so contactor I only will herein be shown and described in detail. Said contactor includes a stationary contact 15 mounted on an insulating board It, and a movable contact ll engageable with said stationary contact. Said movable contact is moun ed on a pivoted arm l9, which is pivoted intermediate its ends to a swinging arm 28, transversely pivoted to a stationary support bracket 2|. A coil spring 22 is interposed between the insulating board l6 and the free end of the arm i9 and is adapted to move the contact ii to an open position with a wiping action. The swinging arm 20 is provided with an engaging abutment 2-3 projecting outwardly therefrom, which is engaged with an engaging member 25 on the end of a plunger 25. Said plunger is slidably mounted in a bearing 25, carried in an end wall of the casing IE, and extends outwardly from said easing into a fluid chamber so, formed in a cylinder 3! secured to the outside of said casing. A fitting 32 connects said fluid chamber with a distributor valve 33 through a pipe 9|. Suitable packing is provided to prevent fluid from entering said casing. Thus when fluid is admitted to the chamber 30, the plunger '25 is moved in a direction to engage the contact l with the contact H, the spring 22 serving to disengage said contacts, when pressure is released from said chamber. The fluid operating mechanism for the contactor is entirely outside of the contactor casing, so that no fluid will enter said casing. A leakage drain (not shown) may be provided to permit fluid which may leak past said plunger to return to the fluid storage tank.

Referring now in particular to the fluid diagram illustrated in Figure 1, a fluid pump i5 is provided to effect pressure in the system. Said pump is connected with an accumulator 35 by means of a pipe line 44, which accumulator serves as a fluid storage tank for the hydraulic system. Said accumulator may be of any well known form and, as herein shown, includes a cylindrical tank 36 having a cover 31. Said cover is provided with an inwardly extending cylindrical portion 38, extending within and opening into said tank. A cylindrical piston 39 is mounted on said cylindrical portion 38, for slidable movement with respect thereto. Said piston has a closed inner end and a flanged portion 40, adapted to abut the inside of said cover 31, when said piston is in a retracted position. A pair of concentrically arranged compression springs 4i and 42 are interposed between the bottom of said tank and the inside of said flange of said piston, to urge said piston into a, retracted position.

A high pressure pipe line 43 connects the inwardly extending cylindrical portion 38 of said accumulator with the pump 45 through a relief valve ifi, so that pressure in the fluid system will supply pressure to said cylinder 38 and cylindrical piston 39 and move said piston against the compression springs M and 42, to compress said springs. The strength of said springs is such that fluid under pressure accumulated in said cylinder and piston, will be supplied to the system through said springs, whenever said fluid pump stops.

The pump 45, which supplies fluid under pressure to said accumulator and to the hydraulic system, is herein shown as being a well known form of gear pump and is connected with the relief valve 46 by means of a pipe line 41. Said relief valve has connection with the pipe line 43, leading to the pressure side of the accumulator, by means or" the pipe line 4 3, which is also connected to a pressure pipe line 50, leading to a control valve 5|, which serves to supply fluid to the distributor valve 33 at progressively increasing or decreasing pressures, through a control pipe line 52. A low pressure pipe line 53 leads from said relief valve to the cylindrical tank 3% of the accumulator 35.

The relief valve 46 is so arranged that under normal pressures fluid will pass from the pipe line 41 through a chamber 54 of said valve, through a passageway 55, and chamber 56, to and through a check valve 5i to the pipe line M. Upon overload, fluid under pressure in the chamber 55 will move a piston 58 in said chamber 56 against a spring 59, to a position to open a port to a passageway Eli, to permit fluid under pressure to engage the under side of a piston ill in the chamber 54. This will move said piston against a spring 62 and open a port leading to a passageway 63, to bypass fluid through said passageway to the tank 36 of accumulator 35, through the pipe 53. Upon the release of pressure, the spring 59 will move the piston 58 in a direction to close the passageway fill to fluid under pressure and open said passageway to the return line 53. At this time pressure will be relieved from the piston 6!, and the spring 62 will move said piston in a direction to close the passageway 53.

A pipe line fit leads from the pipe line 5% to a l-way valve 65, which serves as a reversing valve, for reversing the direction of the flow of fluid to a reversing cylinder 66. Said cylinder is provided to operate a reverse drum 69 for the motors of the locomotive and has a piston 61 movable therein, which is connected with said reverse drum by means of a depending pin "iii (see Figures 3 and l). Said reversing cylinder 66 is shown as being mounted on the outside of a casing 68 for said reverse drum and the contacts therefor. The pin 10 depends from said piston, intermediate the ends thereof, and ex tends through a slot H in the lower portion of said cylinder and has engagement at its lower end with a slotted lever arm 12, secured to the upper end of a shaft 13, upon which said reverse drum is mounted. Rectilinear movement of said piston in one direction or another will thus turn said reverse drum 69 to a forward or reverse position in an obvious manner.

The body of the reversing cylinder 66 is provided with a longitudinally extending pressure passageway 74 opening into said cylinder at 1ongitudinally spaced points, which are spaced equally from the transverse center of said cylinder so that one or the other openings to said passageway will be uncovered by said piston when said piston is in one extreme position or another. Said passageway is connected with a pressure pipe 15, which is connected with the distributor valve 33, for supplying fluid under pressure to the fluid-operating mechanism for the contactors I to 8 inclusive, in a manner which will hereinafter more clearly appear as this specification proceeds.

Since the passageway 14 is only open to the cylinder 68, when the piston ST is in one extreme position or another and the reverse drum is in either a forward or reverse position, fluid under pressure can only flow from reversing cylinder E6 to the distributor valve 33, when said reverse drum is in one of these positions. Thus, a hydraulic interlock is provided between said distributor valve and reverse drum, to prevent operation of said distributor valve, until said reverse drum is in the proper operating position.

Another passageway 76 is provided in the cylinder 66 to take care of any leakage between the piston ii! and the walls of said cylinder. A pipe l'l leads from said passageway to a pipe 18, which connects with the drain pipe 53, leading to the storage tank 36 of the accumulator 35. t

The distributor valve 33 is provided with a cylindrical chamber 8!, having a piston 82 movable therein. Said piston has three spaced apart lands 83, 84 and 35, the land 83 being at the end of said piston adjacent the inlet from the control pipe 52, so that fluid under pressure, entering said valve from said pipe, will move said piston against a coil spring 36, interposed between the inner end of said chamber and the end of said piston opposite from the land 83.

A drain passageway 88 is provided in the body of the distributor valve 33 and leads from a position between the lands 83 and 84 to a position above the land 85, when the piston 82 is in an extreme on position, to take care of any leakage of fluid past said lands 83, B4 and 85. Said drain passageway is connected with the pipe I8, Which leads to the tank 36 of accumulator 35.

The pressure pipe I5 enters the distributor valve 33, intermediate the ends thereof at a point disposed adjacent the lower end of the land 85, when the piston 82 is at an extreme on position and the spring 86 is extended, as in Figure l. The lands 84 and 85 are so spaced that fluid under pressure will be supplied in the space between said lands by said pressure pipe, in all positions of said piston in said cylindrical chamber 8i. It should be noted that fluid admitted from the pipe I5 acts equally in opposite directions on the piston 82, so has no tendency to move said piston in the direction of its axis.

Pipes 99, SI, 92, 93, 9 and 95 lead from ports in the chamber 3!, which are disposed on the opposite side of the land 85 from the lands 83 and 84, when the piston 82 is in an ofi position. Said pipes are so arranged that the respective passageways connecting said pipes to the chamber M will be successively uncovered by the land 85, to admit fluid under pressure from the pipe I5 thereto, upon movement of the piston 82 against the spring 89. Thus, as the piston 82 moves to successively uncover the passageways 90 to 95 inclusive, the contactors associated therewith will be closed in the hereinbefore described manner, to connect the motors of the locomotive in the main line circuit, and to cut out the resistance I3 from the motor circuit, step by step, under control of the operator.

The strength of the spring 85 is such that the piston 92 will move to uncover the passageway leading from the pipe 99 when fluid enters the chamber 8! from the pipe 52 at a predetermined pressure, and will uncover the next passageway when the fluid pressure increases a predetermined amount, and so on until all of the passageways are uncovered step by step.

The control valve 5i. provided to supply fluid under pressure to the distributor valve 33 at uniformly increasin or decreasing pressures, which change step by step for each port opening of said distributor valve, as a control handle '19 of said valve is turned by the operator in one direction or another, is in the form of a triple valve including a block 95 having three valve elements 91, 98 and 99 therein controlled in. unison by the control handle I9. Said valve is clearly shown and described in Patent No. 2,383,894, of which this is a division, so will only herein be shown and described in so far as is necessary to make my present invention clearly understandable.

The valve element 91 is of the piston type and serves as a charging valve for controlling the admission of fluid under pressure to the pressure side of the valve element 98, which is of the poppet type. The valve 98 includes separate pressure and release valves I5I and I55 of the poppet type, which are adapted to open practically simultaneously on the slightest movement of their control means, so that said valve element 98 serves as a pressure adjusting valve when used in conjunction with the valve elements 9'! and 99, to adjust the pressure in the control line 52 at the proper pressure at the same positions of the control handle, with little or no error when the triple valve mechanism is turned in an on or an off direction. The valve element 99 is similar to the valve element 91 and serves as a discharge valve to release fluid discharged through the valve element 98 to the return. This last mentioned valve element and the valve element 9'! also serve to maintain a predetermined pressure difference on opposite sides of the poppet valve element 98, to reduce any pressure inaccuracies which might be caused by an unbalanced pressure on the valve seat areas of said poppet valves Itii and I55.

The valve elements 9?, 98 and 99 communicate with three aligned cylindrical chambers I09, IIH and I92 formed in the block 96 of the valve element 5I Said chambers are each connected with the low pressure side of the accumulator 35 by means of passageways I93, I93 connected to the return line 53. Said chambers besides forming return passageways for the fluid also form enclosures for the control means for said respective valve elements 91, 98 and 99.

Operation of the valve elements 9'5, 98 and 99 is controlled by means of a gear I95, on a shaft 89, which has the control handle 79 mounted on its upper end (see Figures 5 and 6). The teeth of said gear have elongated faces and mesh with teeth formed in cylindrical valve operating sleeves I01, I 08 and I09, which are slidably mounted Within the chambers I99, [9i and )2 respectively. Said valve operating sleeves are each mounted on a flanged portion of a hollow supporting member I l I which is closed at its inner end, and which extends within each sleeve (see Figure 6). Each of said hollow supporting members is slidably mounted on a pilot H2, which is bored to admit fluid therethrough to the inside of its associated supporting member, to exert a pressure on said supporting member in a direction to move said member along said pilot.

A compression spring lld extends within the valve operating member IQ? of valve element 97 and is seated at one of its ends in the flanged portion of the member l l I. The opposite end of said spring abuts a washer F on a seat I45, freely mounted on the inner or right-hand end of a piston valve H5 for the valve element 81. The connection between said seat and piston valve is loose, to avoid binding between said seat and valve and to cause an even pressure to be exerted on said valve by said spring.

In a like manner, a compression spring II "I, in the chamber (9!, extends within the valve operating sleeve I98 of valve element 98 and is provided to open said valve upon compression of said spring by turning movement of the control handle l9.

The valve operating sleeve 299 of valve element 99 also has a compression spring I22 seated therein, for operating a piston valve l24 of said valve element.

Fluid under pressure from the accumulator 35 enters the charging valve element 9] through a passageway I25, connected with the pressure pipe 59. This passageway is connected with said valve element by a port I21 in a valve cylinder I28 for said valve element. Said passageway is connected with the dischar e valve element 99 by a port I14 in a valve cylinder l5! of said valve element. A passageway t lt connects said valve element 97 with the pressure side of the adjusting valve element 98, and a passageway I69 on the discharge side of said pressure adjusting valve element connects said pressure adjustin valve with the discharge valve element 99.

The piston valve I 56 of the charging valve element 91 has a land or piston I29 at the left-hand end thereof which laps the port I 27 and which serves to control opening or closing thereof. Said piston valve is drilled longitudinally and is cross drilled to permit fluid to pass therethrough and balance said valve, and also to permit the discharge of fluid through the chamber IUI and passageways I93, I03, when a land or piston I3I of said valve. adjacent the chamber It"), is open to said chamber. When said piston valve is moved to the left through the spring II I, fluid under pressure will enter the valve cylinder I28 and a passageway MI which leads to the pilot I I2 for the valve operating sleeve I01, to balance the pressure of the spring IM against said valve operating sleeve and the control handle 79. Fluid will also flow through a passageway I45 to the pressure adjusting valve 98.

A piston valve I24 of the discharge valve element 99 is slidably mounted in a valve cylinder I51. Said piston valve is provided with a land I69 at the left-hand end thereof, adapted to control the passage of fluid into said valve cylinder through the port I74, and is provided with a land I'II at the opposite end thereof, adaptedto control the discharge of fluid to the return through the chamber I62. Said piston valve is drilled longitudinally and is cross drilled to permit fluid to pass therethrough and balance said valve, and also to permit the discharge of fluid through the chamber I92 when the land MI is open to said chamber.

When the valve I69 of the valve element 99 is open, fluid will flow through the valve cylinder I57 in the space between the lands of the piston valve I24 through the passageway Ito and a passageway lit to and through the pilot IIZ of the valve operating member I98, to balance the pressure the spring I22 exerts against said piston valve. Fluid will also flow to the discharge side of the pressure adjusting valve element 98, to exert a back pressure on said pressure adjusting valve and overcome the unbalanced pressure on the valve seat of said valve.

The pressure adjusting valve element 98 includes the poppet valve I5I which controls the admission of fluid to the control line 52, and the poppet valve I56 which controls the discharge of fluid from said control line. Said pressure adjusting valve also includes a plunger Id? slidably mounted in a valve cylinder M9. The left-hand end of said valve cylinder is shaped to form a seat which is adapted to be engaged by the righthand end of an enlarged portion I50 of said plunger I II, to form the poppet valve ISI which will open or close upon a very slight movement of said plunger. Said poppet valve is adapted to open or close a passageway through said valve cylinder I49, leading to a passageway I53 in said cylinder, which communicates with a passageway I26 and the control line 52, for supplying fluid under pressure to the distributor valve 33. A passageway I54 leads from the passageway I26 to and through the pilot for the valve operating sleeve I08 and to the hollow member II I for said valve operating sleeve, for balancing the spring pressure against said valve operating sleeve and the control handle I9.

The right-hand portion of the valve cylinder I49 has a hollow piston IIS slidably mounted therein. Said hollow piston has the right-hand end of the plunger I I'I slidably mounted therein. The left-hand end of said hollow piston is shaped to form a seat for the right-hand end of an enlarged valve portion I55 of said plunger IE'I, to form a poppet valve I56 which controls the flow 8 of fluid through the discharge passageway I60, to the discharge valve element 99.

Displacement of the spring II l toward the valve cylinder I49 will move the hollow piston I I9 and plunger M7 in a direction to open the poppet valve I5I, to admit fluid under pressure to the pressure line I53. Fluid pressure exerted on said hollow piston to the right, against the compression spring I Ii, will tend to move said hollow piston to the right to open the valve I56 and permit the discharge of fluid through the passageway Itil.

The plunger M'I is longitudinally drilled from the left-hand end thereof and is cross drilled just to the right of the valve IEI, to admit fluid under pressure to the right-hand end of said plunger. Pressure is exerted on the right-hand end of said plunger, to balance said plunger except for the unbalanced pressures in the annular spaces under the valves i5l and I555, through a passageway I59 in the hollow piston H9.

When the control handle I9 is turned from an on. position to the first on position, fluid from the accumulator 35 will be admitted by the piston I29 through the port I2? and through the passageway IMF, to build up'pressure in said passageway until the poppet valve IEiI is opened by its spring I H, to admit fluid under a predetermined pressure to the passageway I25 and the pressure line 52, to the head end of the piston 82 of the distributor valve 33. When said control handle is on the first on position, fluid will be supplied to said distributor valve at a pressure sufficient to open the port leading to the pipe Gill and permit fluid from the pressure line '55 to pass through said pipe and close the first contactor.

As the control handle I9 is turned to the next on position, the tension of the springs IM, H1 and IIS will be increased a predetermined amount. This will increase the pressure required to close the port I2? and will thus cause a predetermined increase in pressure in the passage way I26 and pressure line 52, to move the piston 82 against the spring 86 a distance sufficient to open the next port, which leads to the pipe 9!, to admit pressure to said pipe and close the second contactor. This operation is continued until all of the ports leading to the passageways 93, 94, and have been opened and the locomotive is in the fully on position.

When turning the control handle in an opposite direction, fluid pressure against the piston 83 will be progressively decreased step by step, to permit the spring 86 to move the piston 82 in a direction to progressively close the ports leading from the passageways 95, 94, 93, 92, Ill and 90, respectively, until the controller is in a fully off position.

A notching cam 81 on shaft 89 for the control handle it is provided with a plurality of spaced notches I'IB, Ila formed in the periphery thereof, which designate the various positions at which definite step by step pressures are established and maintained in the control line 52, so that the distributor valve 33 will have a full opening of the corresponding port. The various positions of said control handle are indexed by means of a roller I19 on the end of a rocking arm I88, which is yieldably pressed into engagement with said notches I78 by means of a spring IEII, engaging said rocking arm.

An interlocking connection is provided between the control valve El and the 4-way reversing valve 65, to prevent operation of said reversing valve except when said control valve is in an off position, and to prevent operation of said control valve except when said reverse valve is in a forward or a reverse position. Said interlocking connection, as herein shown, includes a disk I83 secured to the shaft 89, just above the notching cam 87, and adapted to be engaged by an engaging end I84 of a rocking arm I85. Said disk is provided with a notch I 86 on the face thereof, which corresponds with the off position of said control valve, and which is adapted to be engaged by said projecting engaging end. Said roclL'ng arm is provided with an engaging end I 89, spaced from and extending in an opposite direction from the engaging end I84, which is adapted to register for engagement with either one of a pair of notches I90, I90 on a. locking plate I9I, which is secured to a shaft I92 for said reverse valve 65.

When the control valve is in an off position, the projecting end I 84 of the rocking arm I 85 may engage the notches I 86, I 86 of the disk I83. When said end of said rocking arm is in engagement with said recessed portion of said disk, the locking plate I9I and valve shaft I92 will be free to pivot. When the reversing valve is in an intermediate position, between an extreme forward or reverse position, the engaging end I89 of the arm I 85 will engage the high spot between the notches I90, I90 and the engaging end I84 will be held in engagement with the recessed portion I86, to lock the control handle 19 against turning until the locking plate I 9| is in a position to permit the engaging end I89 to drop into either one of the notches I90, I90, at which time said reverse drum will be in either a forward or reverse position. When said engaging end I 84 is moved out of engagement of said notch I86, said engaging end I89, engaging either of said notches I90, I90, will be held in engagement with either of said notches by said engaging end I89 and star' wheel, to lock said reversing valve from turning movement until said control handle I9 has been moved to turn the control valve 5| to an extreme off position, so said engaging end I84 may drop into the notch I86.

While I have herein shown and described one form in which my invention may be embodied, it will be understood that the construction thereof and the arrangement of the various parts may be altered without departing from the spirit and scope thereof. Furthermore, I do not wish to be construed as limiting my invention to the specific embodiment illustrated, excepting as it may be limited in the appended claims;

I claim as my invention:

1. In a fluid-operated controller, for controlling an electrical circuit or the like, a plurality of devices to be actuated, a plurality of fluid pressure means for actuating said devices in a predetermined order, a distributor valve for supplying fluid under pressure to said fluid pressure means in said predetermined order, another device to be actuated, a fluid cylinder, a doubleacting piston within said cylinder, an operative connection from said piston to said other device for moving the latter to either one of two predetermined positions, fluid connections to opposite ends of said cylinder, a reverse valve for controlling the admission of fluid to either end of said cylinder, to move said piston therein in one direction or another, a passageway leading from two spaced apart openings along said cylinder to said distributor valve for supplying fluid under pressure thereto and to said fluid means through said distributor valve, said piston being adapted to close each of said openings to said passageway, except when in a position to move said other device to one of its predetermined positions, and when in either such position, to open the corresponding opening to fluid from the end of said cylinder with which said opening is asso ciated, to prevent operation of said first named devices except when said second device is in either one of its predetermined positions, a control valve for supplying fluid under pressure to said distributor valve at pressures increasing or decreasing step by step to progressively actuate said distributor valve and thereby actuate said plurality oi devices, and a mechanical interlocking connection between said control valve and said reverse valve, to prevent operation of said reverse valve except when said control valve is in an off position.

2. In a fluid-operated controller for controlling an electrical circuit or the like, a plurality of devices to be actuated, a plurality of fluid pressure means for actuating said devices in a predetermined order, a distributor valve for supplying fluid under pressure to said fluid pressure means in said predetermined order, another device to be actuated, a fluid cylinder, a piston within said cylinder, an operative connection between said piston and said other device for moving the latter to either one of two predetermined positions, fluid connections to said cylinder, at

reverse valve for controlling the admission of fluid to said cylinder through said fluid connections, a passageway leadin from two spaced apart openings along said cylinder to said distributor valve for supplying fluid under pressure thereto and for supplying fluid under pressure to said fluid means through said distributor valve, said piston being adapted to close each of said openings to said passageway, except when in a position to move said other device to one of its said predetermined positions, and when in either of such positions to open the corresponding opening to fluid from the end of said cylinder with which said opening is associated, to prevent operation of said first named devices except when said second device is in either one of its predetermined positions, a control Valve for supplying fluid under pressure to said distributor valve to actuate said distributor valve and thereby actuate said plurality of devices, and a mechanical interlocking connection between said control valve and said reverse valve, to prevent operation of said reverse valve except when said control valve is in an off position.

WILLIAM W. SLOANE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 684,609 Hill Oct. 15, 1901 1,005,420 Darlington Oct. 10, 1911 2,102,294 Taliaferro et al Dec. 14, 1937 2,326,911 Aikman Aug. 17, 1943 2,259,768 Naylor Oct. 21, 1941 1,199,640 Vincent Sept. 26, 1916 2,273,171 Bennett Feb. 17, 1942 2,185,449 Veenschoten Jan. 2, 1940 FOREIGN PATENTS Number Country Date 765,354 French (Baudet) 1934 842,641 French (Vincelli) 1939 

